Mattresses that have adjustable relief area allow expectant mothers to sleep in various positions with greater comfort than standard mattresses. However, such mattresses typically provide only adjustable relief in a vertical direction from the top surface of the mattress. While mattresses with such relief may benefit some expectant mothers, these mattresses fail to take into account the various body shapes and sizes of expectant mothers. A particular woman's height, weight, and how the woman carries the baby may greatly impact the efficacy of a mattress with abdominal relief, or even render the mattress unusable for the woman. This is because the relief volume may not adequately accommodate the woman's abdomen in a manner that offers adequate relief and comfort during pregnancy. Alternatively, a particular mattress may offer adequate relief during a first or second trimester, but during the later stages of pregnancy the mattress may no longer be able to offer adequate relief.